The liquid phase epoxidation of olefins with hydrogen peroxide catalyzed by a fixed bed titanium silicalite catalyst is known from EP 0 100 119 A1. The reaction is usually carried out in a methanol solvent to achieve high reaction rate and product selectivity. Continuous epoxidation is achieved by passing a mixture comprising olefin, hydrogen peroxide and methanol through a fixed bed of the epoxidation catalyst, as described in WO 99/28029, WO 01/10855 and EP 1 085 017 A1.
EP 757 045 A1 teaches that in an epoxidation process where an olefin is reacted with hydrogen peroxide in the presence of a titanium-containing molecular sieve catalyst and a salt, the tendency of the catalyst to produce oxygen as it ages due to non-selective decomposition of the hydrogen peroxide may be counteracted by the addition of a chelating agent. Polyphosphonic acids as well as their alkali metal, alkaline earth metal and ammonium salts may be used as chelating agents. EP 757 045 A1 discloses an epoxidation of propene in a continuous stirred tank reactor using an extrudate containing TS-1 titanium silicalite, where aminotrimethylenephosphonic acid is added to a feed stream containing 2.5% by weight hydrogen peroxide, 73% by weight isopropanol, 24% by weight water, 0.2% by weight methanol, 0.29% by weight acetic acid and 0.1% by weight formic acid.